Induction cooktops have many advantages over other cooking methods, including efficiency, controllability, and safety. Each hob of an induction cook-top contains one or more coils made of ferromagnetic material. As an alternating current is passed through these coils in the hob, a magnetic field of the same frequency is produced. When a magnetic-based pan is placed on the hob, the magnetic field induces a current in the pan. The internal resistance of the pan causes heat to be dissipated, following the Joule effect and the pan itself, and not the cook-top, heats up and cooks the food. When the pan is removed from the cook-top, the energy transfer stops. The result is a flameless method of cooking in which the cook-top surface remains cool at all times. Control of cooking temperatures is achieved quickly, efficiently, and with great precession.
While induction cooking can be utilized in connection with any type of cookware or servingware, such as frying pans, woks, pots, and the like, an induction cook-top can only heat magnetic-based materials that allow an induced current to flow within them, such as iron and steel. Thus, aluminum, copper, glass or pyrex items cannot be heated by an induction cook-top. Examples of items manufactured so that they are heatable by induction are disclosed in U.S. patent application Ser. No. 10/833,356, the entire disclosure of which is incorporated herein by reference in its entirety. Although a number of materials can be utilized for fabrication of a pan body capable of induction heating, the construction of a multi-ply body comprising layers of several different materials is quite common. The specific material used for each ply or layer, the thickness of each layer, and the total number of layers will vary depending upon the size, shape, desired appearance and desired heating characteristics of the pan. In an exemplary embodiment, the pan body is a 5-ply construction, including a first layer of magnetic stainless steel forming the interior cooking surface of the pan, a second inner-layer of 3003 pure aluminum, a third inner-layer of 1145 aluminum alloy, a fourth inner-layer of 1145 aluminum, and a fifth layer of magnetic stainless steel forming the exterior surface of the pan. The two surface layers of magnetic stainless steel provide strength, durability, easy cleaning and a long-lasting, attractive appearance to the pan body. The exterior surface layer of magnetic stainless steel builds up heat generated from a stove cook-top (either by conduction in a traditional stove, or by induction utilizing the ferromagnetic properties of the steel in an induction stove) generally at the center of the base of the pan body. The three layers of aluminum and aluminum alloy, which form an aluminum core for the pan, absorb heat quickly from the exterior layer of steel, and smoothly and evenly distribute the heat through conduction across the bottom and sides of the pan body to the inner layer of steel.
Although cookware manufactured of non-magnetic materials such as aluminum, copper, glass or pyrex are not capable of induction heating, there are many advantages to non-magnetic materials that are not present in magnetic materials such as steel or iron. For example, aluminum cookware is preferred by many cooks due to its lighter weight. Therefore, it would be beneficial to provide a means for utilizing cookware and/or servingware manufactured primarily of non-magnetic materials with induction heating systems.